Orion Arm

A minor spiral arm of the Milky
Way Galaxy close to the inner edge of which the Sun is located. Its
name derives from the fact that the stars closest to the Sun which actually
lie within the arm are in the constellation of Orion,
about 2,000 light-years away. These include the bright stars of Orion's
Belt, Alnilam, Alnitak, and Mintaka. The Orion Arm is also called the
Orion Spur or Local Arm.

It is important to recognize that the Orion Arm is not a physical structure
but a zone where new stars have been created, by the passage of a density
wave, and have subsequently illuminated the interstellar
medium around them. The picturesque analogy has been drawn between spiral
arms and bands of luminescent plankton churned up in the wake of a ship.